1. Technical Field
The present invention relates generally to a fuel efficient driving technique for a vehicle, and more particularly to a system for fuel-efficient driving, which provides a driver with information on a road so that the vehicle can be operated in an optimal fuel-efficiency.
2. Related Art
Optimization of fuel efficiency of vehicles has become a very important issue for automobile manufacturers and consumers. Intensive researches have been made to provide fuel efficient vehicles by, for example, developing a lean burn engine or increasing the efficiency of an engine and a transmission.
One of the techniques for providing fuel-efficient driving is to provide information about the current fuel efficiency of a vehicle to a display unit such as to allow the driver to determine whether to increase the speed of the vehicle, as disclosed in U.S. Pat. No. 4,166,382.
A conventional system for providing fuel-efficient driving information, as disclosed in U.S. Pat. No. 6,092,021, directs a driver to increase or decrease the speed of the vehicle by displaying uneconomical, semi-economical, and economical regions on the basis of information about fuel efficiency and power-related information measured from a sensor or sensors in the engine or transmission and power-related information acquired from an accelerator and a brake pedal.
The conventional system for providing fuel-efficient driving information is described in detail with reference to FIG. 1.
The conventional system classifies driving regions into uneconomical, semi-economical and economical regions according to the degree of acceleration and deceleration for each road section and indicates the current fuel efficiency of the vehicle falls within one of the ranges to enable the driver to consider the current fuel efficiency state in increasing or decreasing the speed of the vehicle.
However, the conventional system applies the criteria for general rectilinear roads curved and inclined roads, which may lower the reliability of the system and cause vehicle accidents.
That is, in the case of a curved road, it is advantageous in terms of fuel efficiency to decrease the speed of a vehicle well before the vehicle enters a corner of the curved road and slowly decrease the speed until the vehicle passes the corner completely. However, the conventional system indicates that the current fuel efficiency is in an economical region if the speed of the vehicle is maintained immediately before the vehicle enters the corner, but indicates that the current fuel efficiency is in a semi-economical or uneconomical region if the speed of the vehicle is decreased before the vehicle enters the corner. Accordingly, in the case where a driver heeds the information that is provided from the system, he or she decreases the speed rapidly when the vehicle completely enters the corner, causing a decrease in fuel efficiency. For example, a driver is aware that a road ahead is a curved road when his or her vehicle has entered the curved road while traveling at a speed of 50 mph, and starts to brake the vehicle. In this case, the speed of the vehicle is rapidly decreased from 50 mph to 20 mph and is then rapidly decreased from 20 mph to 6 mph, which causes a decrease in fuel efficiency.
In the same manner, in the case of an inclined road, it is efficient to acquire sufficient power before the vehicle enters the inclined road and ascend the incline using a momentum generated by the power. However, the conventional system is problematic in that fuel efficiency is decreased because an accelerator is excessively pushed down due to the lack of drive force on the inclined road.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.